package org.nhin.test;

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common
 * Development and Distribution License("CDDL") (collectively, the
 * "License"). You may not use this file except in compliance with the
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 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
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 * Notice in each file and include the License file at
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 * particular file as subject to the "Classpath" exception as provided
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 * accompanied this code. If applicable, add the following below the
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 *
 * The Original Software is NetBeans. The Initial Developer of the Original
 * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
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 * If you wish your version of this file to be governed by only the CDDL
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 * under the [CDDL or GPL Version 2] license." If you do not indicate a
 * single choice of license, a recipient has the option to distribute
 * your version of this file under either the CDDL, the GPL Version 2 or
 * to extend the choice of license to its licensees as provided above.
 * However, if you add GPL Version 2 code and therefore, elected the GPL
 * Version 2 license, then the option applies only if the new code is
 * made subject to such option by the copyright holder.
 */

/**
 * This class provides Base64 encoding/decoding.
 */
public class Base64 {
    private Base64() {
        // Avoid instantiation of this class
    }

    /**
     * Encodes datas using base64 encoding.
     *
     * @param   abyte0  data for encoding
     *
     * @return  encoded string
     */
    static String encode(final byte[] abyte0) {
        final StringBuffer stringbuffer = new StringBuffer();
        for (int i = 0; i < abyte0.length; i += 3)
            stringbuffer.append(encodeBlock(abyte0, i));

        return stringbuffer.toString();
    }

    private static char[] encodeBlock(final byte[] abyte0, final int i) {
        int j = 0;
        final int k = abyte0.length - i - 1;
        final int l = (k < 2) ? k : 2;
        for (int i1 = 0; i1 <= l; i1++) {
            final byte byte0 = abyte0[i + i1];
            final int j1 = (byte0 >= 0) ? ((int) (byte0)) : (byte0 + 256);
            j += j1 << (8 * (2 - i1));
        }

        char[] ac = new char[4];
        for (int k1 = 0; k1 < 4; k1++) {
            final int l1 = (j >>> (6 * (3 - k1))) & 0x3f;
            ac[k1] = getChar(l1);
        }

        if (k < 1)
            ac[2] = '=';
        if (k < 2)
            ac[3] = '=';
        return ac;
    }

    private static char getChar(final int i) {
        if ((i >= 0) && (i <= 25))
            return (char) (65 + i);
        if ((i >= 26) && (i <= 51))
            return (char) (97 + (i - 26));
        if ((i >= 52) && (i <= 61))
            return (char) (48 + (i - 52));
        if (i == 62)
            return '+';
        return (i != 63) ? '?' : '/';
    }

    /**
     * Decode string using Base64 encoding.
     *
     * @param   s  string for decoding
     *
     * @return  decoded data
     */
    static byte[] decode(final String s) {
        if (s.length() == 0)
            return new byte[0];
        int i = 0;
        for (int j = s.length() - 1; (j > 0) && (s.charAt(j) == '='); j--)
            i++;

        final int k = ((s.length() * 6) / 8) - i;
        byte[] abyte0 = new byte[k];
        int l = 0;
        for (int i1 = 0; i1 < s.length(); i1 += 4) {
            final int j1 =
                (getValue(s.charAt(i1)) << 18) + (getValue(s.charAt(i1 + 1)) << 12) + (getValue(s.charAt(i1 + 2)) << 6) +
                getValue(s.charAt(i1 + 3));
            for (int k1 = 0; (k1 < 3) && ((l + k1) < abyte0.length); k1++)
                abyte0[l + k1] = (byte) ((j1 >> (8 * (2 - k1))) & 0xff);

            l += 3;
        }
        return abyte0;
    }

    private static int getValue(final char c) {
        if ((c >= 'A') && (c <= 'Z'))
            return c - 65;
        if ((c >= 'a') && (c <= 'z'))
            return (c - 97) + 26;
        if ((c >= '0') && (c <= '9'))
            return (c - 48) + 52;
        if (c == '+')
            return 62;
        if (c == '/')
            return 63;
        return (c != '=') ? -1 : 0;
    }
}
